Table of contents

1. Introduction to Anatomy & Physiology5h 43m
2. Cell Chemistry & Cell Components12h 36m
3. Energy & Cell Processes10h 6m
4. Tissues & Histology10h 3m
5. Integumentary System2h 20m
6. Bones & Skeletal Tissue2h 16m
7. The Skeletal System2h 35m
8. Joints2h 17m
9. Muscle Tissue2h 33m
10. Muscles1h 11m
11. Nervous Tissue and Nervous System1h 35m
12. The Central Nervous System1h 6m
- Introduction to the Central Nervous System
  18m
- The Cerebrum
  48m
13. The Peripheral Nervous System1h 26m
14. The Autonomic Nervous System1h 38m
15. The Special Senses2h 41m
16. The Endocrine System2h 48m
17. The Blood3h 22m
18. The Heart3h 42m
19. The Blood Vessels3h 35m
20. The Lymphatic System3h 16m
21. The Immune System14h 37m
22. The Respiratory System3h 20m
23. The Digestive System2h 5m
24. Metabolism and Nutrition4h 0m
25. The Urinary System2h 39m
26. Fluid and Electrolyte Balance, Acid Base Balance37m
27. The Reproductive System2h 5m
28. Human Development1h 21m
29. Heredity3h 32m

21. The Immune System

First-Line Defenses: Chemical Barriers

Anatomy & Physiology

21. The Immune System

First-Line Defenses: Chemical Barriers

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2:38 minutes

Problem 1

Textbook Question

All of the following are considered innate body defenses except:
a. Complement
b. Phagocytosis
c. Antibodies
d. Lysozyme
e. Inflammation

Verified step by step guidance

Understand the concept of innate body defenses: These are nonspecific defense mechanisms that come into play immediately or within hours of an antigen's appearance in the body. They include physical barriers, chemical barriers, and cellular responses.

Review the options provided: a. Complement, b. Phagocytosis, c. Antibodies, d. Lysozyme, e. Inflammation. Determine which of these are innate defenses and which are adaptive defenses.

Recall that antibodies are part of the adaptive immune system, not the innate immune system. They are produced by B cells in response to specific antigens and are highly specific to the pathogens they target.

Confirm that the other options (Complement, Phagocytosis, Lysozyme, and Inflammation) are indeed innate defenses. Complement is a protein system that enhances immune responses, phagocytosis involves engulfing pathogens, lysozyme is an enzyme that breaks down bacterial cell walls, and inflammation is a nonspecific response to injury or infection.

Conclude that the correct answer is the one that does not belong to the innate immune system, which is antibodies.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Innate Immunity

Innate immunity refers to the body's first line of defense against pathogens, which is present from birth. It includes physical barriers like skin, as well as immune responses that are non-specific, such as inflammation and phagocytosis. This type of immunity acts quickly to prevent infection and does not adapt or improve with exposure to specific pathogens.

Adaptive Immunity

Adaptive immunity is a specialized immune response that develops over time and is characterized by the ability to recognize and remember specific pathogens. This system involves lymphocytes, such as B cells and T cells, which produce antibodies and mount a targeted response upon re-exposure to the same pathogen. Antibodies, which are proteins produced by B cells, are a key component of this adaptive response.

Complement System

The complement system is a group of proteins that play a crucial role in the immune response, particularly in innate immunity. It enhances the ability of antibodies and phagocytic cells to clear pathogens from an organism. The complement system can be activated through various pathways, leading to the lysis of pathogens, opsonization, and inflammation, but it is not considered an adaptive defense mechanism.